Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B33—ADDITIVE MANUFACTURING TECHNOLOGY
  • B33Y—ADDITIVE MANUFACTURING, i.e. MANUFACTURING OF THREE-DIMENSIONAL [3-D] OBJECTS BY ADDITIVE DEPOSITION, ADDITIVE AGGLOMERATION OR ADDITIVE LAYERING, e.g. BY 3-D PRINTING, STEREOLITHOGRAPHY OR SELECTIVE LASER SINTERING
  • B33Y70/00—Materials specially adapted for additive manufacturing
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B33—ADDITIVE MANUFACTURING TECHNOLOGY
  • B33Y—ADDITIVE MANUFACTURING, i.e. MANUFACTURING OF THREE-DIMENSIONAL [3-D] OBJECTS BY ADDITIVE DEPOSITION, ADDITIVE AGGLOMERATION OR ADDITIVE LAYERING, e.g. BY 3-D PRINTING, STEREOLITHOGRAPHY OR SELECTIVE LASER SINTERING
  • B33Y80/00—Products made by additive manufacturing
• • C—CHEMISTRY; METALLURGY
  • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
  • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
  • C04B28/00—Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements
  • C04B28/14—Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements containing calcium sulfate cements
• • C—CHEMISTRY; METALLURGY
  • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
  • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
  • C04B28/00—Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements
  • C04B28/14—Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements containing calcium sulfate cements
  • C04B28/145—Calcium sulfate hemi-hydrate with a specific crystal form
• • C—CHEMISTRY; METALLURGY
  • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
  • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
  • C04B28/00—Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements
  • C04B28/14—Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements containing calcium sulfate cements
  • C04B28/16—Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements containing calcium sulfate cements containing anhydrite, e.g. Keene's cement
• • C—CHEMISTRY; METALLURGY
  • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
  • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
  • C04B38/00—Porous mortars, concrete, artificial stone or ceramic ware; Preparation thereof
  • C04B38/10—Porous mortars, concrete, artificial stone or ceramic ware; Preparation thereof by using foaming agents or by using mechanical means, e.g. adding preformed foam
• • C—CHEMISTRY; METALLURGY
  • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
  • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
  • C04B2111/00—Mortars, concrete or artificial stone or mixtures to prepare them, characterised by specific function, property or use
  • C04B2111/00034—Physico-chemical characteristics of the mixtures
  • C04B2111/00181—Mixtures specially adapted for three-dimensional printing (3DP), stereo-lithography or prototyping
• • C—CHEMISTRY; METALLURGY
  • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
  • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
  • C04B2111/00—Mortars, concrete or artificial stone or mixtures to prepare them, characterised by specific function, property or use
  • C04B2111/00474—Uses not provided for elsewhere in C04B2111/00
  • C04B2111/00663—Uses not provided for elsewhere in C04B2111/00 as filling material for cavities or the like
• • C—CHEMISTRY; METALLURGY
  • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
  • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
  • C04B2111/00—Mortars, concrete or artificial stone or mixtures to prepare them, characterised by specific function, property or use
  • C04B2111/20—Resistance against chemical, physical or biological attack
  • C04B2111/28—Fire resistance, i.e. materials resistant to accidental fires or high temperatures
• • C—CHEMISTRY; METALLURGY
  • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
  • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
  • C04B2111/00—Mortars, concrete or artificial stone or mixtures to prepare them, characterised by specific function, property or use
  • C04B2111/34—Non-shrinking or non-cracking materials

Definitions

• the present invention relates to a method for manufacturing a construction element, especially a construction element comprising a base element that comprises at least on cavity, said cavity being at least partially filled with a mineral foam.
• Such construction elements are for example walls or parts of walls, and may be manufactured by 3-D printing methods.
• Insulating materials are for example mineral wool or foams, either inorganic (e.g. cement foams) or organic (e.g. polyurethane foams).
• FR3085374 proposed, in order to reduce the shrinkage of mineral foams, to use a hydraulic binder comprising binary or ternary mixtures of 20-60wt% gypsum with Calcium Aluminate Cement (CAC), Ordinary Portland Cement (OPC) and/or Calcium Sulfoaluminate Cement (CSA).
• CAC Calcium Aluminate Cement
• OPC Ordinary Portland Cement
• CSA Calcium Sulfoaluminate Cement
• CSA Calcium Sulfoaluminate Cement
• the invention aims at providing a method that makes it possible to propose even more stable mineral foams.
• an object of the invention is a method for manufacturing a construction element comprising:
• the invention also relates to a method for manufacturing a construction element comprising:
• the shrinkage is measured according to the standard EN 13872:2004, using specimens of 40*40*160 mm 3 .
• Another object of the invention is a construction element obtainable by this method.
• the base element preferably comprises two walls facing one another.
• the two walls thus create a cavity or a plurality of cavities.
• the base element is for example a wall for a building or for a house, such as a load-bearing wall or a dividing wall.
• Said base element is preferably made of concrete or mortar.
• Said two wall facing one another may be constructed by any known method, for example by pouring concrete between formworks or by joining masonry elements such as bricks or concrete blocks.
• the method comprises manufacturing said walls by 3D-printing of mortar.
• 3-D printing of mortar also known as additive manufacturing
• a computer-controlled such as a robot
• manufactures three-dimensional objects by depositing a mortar layer by layer.
• Contour Crafting or Cementitious Ink Printing these techniques may be realized in construction scale applications, and their advantages are the integration of the design, planning and construction processes coupled with an increase automation and rationalization of building processes. Savings on labor costs, lower losses and consumption of materials, eliminating formwork, shorter project lengths and capital commitment as well as an increased workspace safety are other driving factors for this technology.
• a wet mortar is continuously produced by mixing a dry mortar composition with water, is pumped and conveyed towards the printer head of a computer-controlled printer, usually a robot or a gantry, and is then deposited as a layer on a previous layer of mortar, usually by being extruded through a nozzle.
• the printer head is moved according to a predetermined scheme, precisely materializing e.g. complex geometries designed by architects, so as to manufacture the final object.
• the height of said walls is preferably at least 1 m, especially at least 2 m.
• the height of the walls is usually below 5 m, even below 4 m.
• the invention is especially useful for elements having a great height, since the shrinkage of the foam is an issue mainly for this kind of elements.
• the base element will frequently be parallelepipedic, but other forms are possible, especially when using 3D-printing techniques.
• the hydraulic binder comprises (or preferably consists of) 20-70wt% of calcium sulfoaluminate cement (CSA), 25-70wt% of Ordinary Portland Cement (OPC) and 5-20wt% of a source of calcium sulfate.
• CSA calcium sulfoaluminate cement
• OPC Ordinary Portland Cement
• this specific ternary composition made it possible to reduce the shrinkage of the mineral foam during hardening.
• the amount of calcium sulfoaluminate cement is preferably 22-60wt%, especially 25-40wt%.
• the amount of Ordinary Portland Cement is preferably 30-70wt%, especially 35-65wt%, even 45-65wt% or 50-65wt%.
• the amount of a source of calcium sulfate is preferably 5-15wt%, especially 7-12wt%. Proportions are given with respect to the weight of hydraulic binder.
• Ordinary Portland Cement is preferably a CEM I cement according to Standard EN 197-1.
• the source of calcium sulfate is preferably selected from gypsum, anhydrite, hemihydrate and mixtures thereof.
• composition comprising a hydraulic binder is preferably a pulverulent mixture.
• the water ratio i.e. the weight ratio of added water to hydraulic binder is preferably 0.30 to 0.60, especially 0.35 to 0.50.
• composition comprising a hydraulic binder may additionally contain additives and/or aggregates.
• the composition comprising a hydraulic binder consists of said hydraulic binder and optionally of additives.
• the mineral slurry is in that case a "cement slurry”.
• the composition comprising a hydraulic binder consists of said hydraulic binder, aggregates and optionally additives.
• the mineral slurry is in that case a "mortar slurry" (or wet mortar).
• Aggregates are for example fillers (such as limestone or dolomitic fillers) and/or sands (such as silica sand). Aggregates may also include lightweight aggregates, especially selected from perlite, vermiculite, expanded glass beads, expanded polystyrene beads, cenospheres, expanded silicates, aerogels and mixtures thereof.
• Aggregates may also include fibers, especially polymeric fibers, for example made of polypropylene or polyvinyl alcohol, especially in an amount of 0.1 to 5wt% with respect to the weight of hydraulic binder. Fibers make it possible to improve the mechanical properties of the foam and reduce the shrinkage thereof.
• the' weight ratio aggregates/hydraulic binder is preferably 10:90 to 70:30.
• additives are preferably selected from polymers, plasticizers, superplasticizers, accelerators, retarders, rheological modifiers (such as cellulose ethers) and mixtures thereof.
• the additives should preferably not contain anti-foaming agents.
• the total amount of additives is preferably 0.5-15wt% with respect to the weight of hydraulic binder.
• Accelerators and retarders are additives that accelerate or retard setting and/or hardening of the hydraulic binder.
• Accelerators include for example lithium carbonate.
• Retarders are for example based on tartaric acid or citric acid, or on sodium salts of such acids.
• (super)plasticizer makes it possible to limit the shrinkage by reducing the water content.
• superplasticizers include polycarboxylate poly(ethylene glycol) esters.
• Polymers are preferably in the form of redispersible polymer powders (RDP).
• RDP redispersible polymer powders
• the amount of polymers is preferably 0.5-10wt%, especially 1-5wt% with respect to the weight of hydraulic binder. The presence of polymers makes it possible to obtain a foam that is less brittle.
• the polymer preferably comprises at least a polymer based on one or more monomers selected from the group including vinyl esters (especially vinyl esters of unbranched or branched alkylcarboxylic acids having from 1 to 15 carbon atoms), methacrylates and acrylates (especially (meth)acrylates of alcohols having from 1 to 10 carbon atoms), methacrylic acid, acrylic acid, vinyl aromatics, olefins, dienes and vinyl halides.
• vinyl esters especially vinyl esters of unbranched or branched alkylcarboxylic acids having from 1 to 15 carbon atoms
• methacrylates and acrylates especially (meth)acrylates of alcohols having from 1 to 10 carbon atoms
• methacrylic acid acrylic acid
• vinyl aromatics especially olefins, dienes and vinyl halides.
• the vinyl esters are preferably vinyl acetate, vinyl propionate, vinyl butyrate, vinyl 2-ethylhexanoate, vinyl laurate, 1-methylvinyl acetate, vinyl pivalate and vinyl esters of alpha-branched monocarboxylic acids having from 5 to 11 carbon atoms.
• Preferred methacrylates or acrylates are methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, propyl acrylate, propyl methacrylate, n-butyl acrylate, n-butyl methacrylate and 2-ethylhexyl acrylate.
• Vinyl aromatics are preferably styrene, methylstyrene and vinyltoluene.
• the preferred vinyl halide is vinyl chloride.
• the preferred olefins are ethylene and propylene, and the preferred dienes are 1,3-butadiene and isoprene.
• Particularly preferred polymers are copolymers of at least two of the abovementioned monomers, especially vinyl acetate-ethylene copolymers, vinyl ester-ethylene-vinyl chloride copolymers ,vinyl acetate copolymers, vinyl acetate-acrylate copolymers, copolymers of methyl methacrylate with n-butyl acrylate and/or 2-ethylhexyl acrylate, copolymers of methyl methacrylate with 1,3-butadiene, vinyl chloride-ethylene copolymers, vinyl chloride-acrylate copolymers, styrene-butadiene copolymers, styrene-acrylate copolymers, vinyl acetate-(meth)acrylic acid-ethylene terpolymers.
• additives and/or aggregates may not be present in the composition comprising a hydraulic binder, but may be added at a later stage, for example in the mineral slurry or in the slurry of mineral foam.
• the mineral slurry and/or the slurry of mineral foam comprises such additives and/or aggregates.
• a liquid-phase accelerator is added to the slurry of mineral foam before filling the cavity, preferably just before filling the cavity. It may alternatively (but less preferably) be added to the mineral slurry. Such a liquid-phase accelerator also contributes to reduce the shrinkage of the mineral foam.
• the liquid-phase accelerator preferably contains calcium salts and/or alkali salts, such as lithium carbonate, sodium carbonate, sodium sulfate and/or calcium nitrate.
• solutions containing calcium nitrate and sodium thiocyanate such as the accelerator sold under the name SikaRapid ® C-100, can be used.
• the weight ratio between the liquid-phase accelerator and the hydraulic binder is preferably 0.01-0.20, especially 0.03-0.10.
• the density of the mineral foam after hardening is preferably 60-250 kg/m 3 , especially80-200 kg/m 3 . Such low densities make it possible to achieve low thermal conductivities, and therefore to improve the thermal resistance of the construction element and the thermal insulation of the building.
• the density of the mineral foam is regulated mainly by playing on the ratio between the mineral slurry and the aqueous foam.
• the ratio R between the volume (or volumetric flow rate) of aqueous foam and the volume (or volumetric flow rate) of mineral slurry is preferably 7 to 20, especially 10 to 18.
• the aqueous foam is preferably obtained by mixing water and a foaming agent or a foam stabilizing agent, then by introducing a gas, especially air, by stirring, bubbling or by injection under pressure.
• a gas especially air
• the average diameter of the bubbles in the aqueous foam is preferably 400 ⁇ m or lower, especially 200 ⁇ m or lower.
• the density of the aqueous foam is preferably 50-100 g/L.
• the foaming agent is preferably a surfactant. According to a preferred example, it is a surfactant derived from proteins or amino acids.
• the aqueous foam comprises the mixture of a cationic surfactant which is a salt (in particular a halide) of quaternary ammonium and of an anionic surfactant which is a salt (in particular an alkaline salt) of a carboxylic acid in C10-C24, for instance potassium stearate.
• a cationic surfactant which is a salt (in particular a halide) of quaternary ammonium
• an anionic surfactant which is a salt (in particular an alkaline salt) of a carboxylic acid in C10-C24, for instance potassium stearate.
• the aqueous foam comprises nanoparticles, in particular made of silica, which have the property of stabilizing the foams.
• foams are called “Pickering foams”.
• Silica nanoparticles may themselves be stabilized by surfactants.
• the concentration of foaming agent (especially of surfactant) in the aqueous foam is preferably 0.5 to 10wt%, especially 1.5 to 6wt%. A higher concentration improves the stability of the foam, but may increase the setting time of the hydraulic binder.
• Mixing the mineral slurry with aqueous foam is preferably carried out with a static mixer.
• the construction element can be manufactured directly at the building construction site.
• the construction element is a prefabricated element, intended to be transported to the building construction site.
• the composition also comprised accelerators (0.15wt% Li 2 CO 3 , 0.2wt% Na 2 CO 3 and 0.2wt% Na 2 SO 4 ) and retarders (0.04wt% of tartaric acid and 0.2wt% of sodium citrate).
• Comparative examples C1-C4 used the following hydraulic binders:
• OPC was a CEM I 52.5 R Portland Cement.
• CSA was a calcium sulfoaluminate cement (i.tech ® ALI PRE from Heidelberg Cement) and gypsum was anhydrite or hemihydrate.
• the mineral slurries were then mixed with an aqueous foam made in a foam generator by using a 3wt% solution of a protein-based surfactant sold under the name "Propump 26".
• the density of the aqueous foam was 70 g/L.
• the "R" ratio as defined above was 14.
• the densities of the mineral foams (after hardening) were around 150-180 kg/m 3 for all the examples.
• Table 1 below shows the results in terms of shrinkage, after 7, 14 and 28 days, measured according to the standard EN 13872:2004, using specimens of 40*40*160 mm 3 .

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Citations (2)

• 2022
  • 2022-01-19 EP EP22315014.5A patent/EP4215506A1/fr active Pending
• 2023
  • 2023-01-18 WO PCT/EP2023/051133 patent/WO2023139126A1/fr unknown

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